Sen. Lindsey Graham, R-S.C., is locked in a fierce battle to defend his Senate seat, which his party has held for nearly two decades, after his opponent, Democrat Jaime Harrison, soared to popularity and crushed records with his fundraising haul in the runup to Election Day. 

Now, Graham is polling only slightly better than Harrison -- 49 to 46 -- according to the most recent tally by ECU Poll of South Carolina.

Here are 5 things to know about the incumbent senator. 

1. Graham initially criticized President Trump as "crazy" and "unfit for office" but is now one of his closest allies. 

Critics have been frustrated at Graham for his flip-flopping position on Trump and have lashed out at him for changing stance on a number of issues, calling him hypocritical.

For example, Graham was one of several Republicans who fiercely opposed then-President Barack Obama's Supreme Court nomination of Merrick Garland nearly eight months before the election. Yet he proceeded to defend Trump's nominee Amy Coney Barrett, who was successfully sworn in to the highest court in the country just seven days before Election Day.

Graham has also raised eyebrows for his close friendship with the late Sen. John McCain, R-Ariz., who Trump personally attacked and insulted prior to his death. 

2. Graham was once a member of the "Gang of Eight"

The bipartisan group -- made up of four Republicans and four Democrats in the Senate -- worked on comprehensive immigration reforms introduced in 2013 but that ultimately failed to gain traction in Congress.

Amongst the policy changes backed by Graham was a path to citizenship for immigrants already living illegally in the country. Further evidence of a shift in his views is Graham's support of Trump's policies after 2016, which veered further right, including building a wall along the U.S.-Mexico border and implementing a travel ban from seven countries with predominantly Muslim populations. 

3. His Democratic challenger has significantly outraised and outspent him this election cycle. 

The South Carolina Senate race has shaped up to be the most expensive in the state's history after Harrison both raised and spent more than $100 million overall, by far the most of any Senate candidate in American history.

Harrison raked in $107.6 million in donations and his campaign spent almost as much, doling out $104.1 million. The previous record was set in 2018 by Sen. Rick Scott, R-Fla., with $85 million, though much of that total was self-funded.

Meanwhile, Graham this cycle raised $72.7 million and spent $60 million, hefty sums had it not been for Harrison's record-setting hauls.  

4. Graham has won his previous general election contests by double-digit margins

This race is the closest Graham has ever faced with a Democratic opponent. 

In 2002, Graham sailed to victory over Democrat Alex Sanders, the former chief judge of the South Carolina Court of Appeals, 54.4% to 44.19%. Again in 2008, Graham beat Democrat Bob Conley 57.52% to 42.25%. He repeated victory for a third time in 2014 when he defeated Brad Hutto by the widest margin yet, 54.27% to 38.78%.

5. Graham is the Chair of the Senate Judiciary Committee

Graham has been a senator for South Carolina since 2003 and assumed his position on the committee in 2019. Prior to entering the Senate, he was a member of the House of Representatives, from South Carolina’s 3rd District, from 1995 to 2003.

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